import java.util.Random;
import java.util.UUID;


public class UUIDUtils {

   public static String getUUID(){
         return UUID.randomUUID().toString().replace("-", "");
    }
   
   //隨機產生數字字母
   public static String getStringRandom() {  
       String val = "";  
       Random random = new Random();  
       
 
//參數length，表示生成100位隨機數  
       for(int i = 0; i < 100; i++) {  
           String charOrNum = random.nextInt(2) % 2 == 0 ? "char" : "num";  
           //輸出字母還是數字  
           if( "char".equalsIgnoreCase(charOrNum) ) {  
               //輸出是大寫字母還是小寫字母  
               int temp = random.nextInt(2) % 2 == 0 ? 65 : 97;  
               val 
 
+= (char)(random.nextInt(26) + temp);  
           } else if( "num".equalsIgnoreCase(charOrNum) ) {  
               val += String.valueOf(random.nextInt(10));  
           }  
       } 
       System.out.println("隨機產生100位數字字母:"+val);
       return val;  
   }  

    public static void main(String[] args) {
        System.out.println(
 
"格式前的UUID:" + UUID.randomUUID().toString());
        System.out.println("格式化後的UUID:" + getUUID());
        getStringRandom();
    }
}

展示:

鏈接:Java隨機生成定長純數字或數字字母混合數

　　1. https://www.cnblogs.com/aGboke/p/5488327.html

　　 2. https://blog.csdn.net/cndmss/article/details/51996876

UUID+隨機數